Participation in many sports involves repeating certain motions over and over again. The consistent ability to perform these motions in a particular way is usually critical to good performance in the sport. Different methods have been found to help participants develop the ability to repeatedly move in a certain way. Increasingly, technology is being used in such methods to improve performance in sports.
Video image analysis is an important part of modern sports training. The ability to see oneself perform a motion helps an individual identify flaws in technique and correct them. Furthermore, video image analysis techniques can be applied to video of a sports motion to help identify aspects of a motion that need changing or identify aspects of a motion performed correctly for positive feedback.
Taking tennis as an example, a tennis player's swing technique is critical to their ability to play different strokes like forehand topspin, backhand volley, serve, and variety of other strokes. Over the years, a preferred tennis swing technique for various strokes has been identified and most tennis players strive to model their swings as closely as possible to the preferred technique. Video image analysis has been used in tennis to improve tennis player's swings. Appropriate swing analysis can contribute to an improvement in the player's skill.
A straightforward form of video image analysis of a tennis sport for example, is simply to record a tennis player's swing for ground stroke, volley, or a serve, and watch it back to identify flaws that cannot be discerned by the player themselves or by a tutor. Video footage can be paused so that individual frames showing a particular swing position can be analyzed.
Another analysis method is to display a player's tennis swing next to that of another, to more easily identify differences compared to a model swing. Some existing methods involve synchronizing the two swings so that corresponding swing positions are shown together, which makes comparison easier.
When capturing video footage of a tennis swing for example, there may be a large amount of footage recorded either side of the swing itself, for example when a player is preparing to serve. Such footage is largely redundant and can make it difficult to quickly identify the actual swing motion and may take up precious memory space in the case of stored digital video data. It is therefore desirable to extract segments of video footage that contain just the swing motion for various strokes.
Some existing methods of golf swing video analysis achieve these aims, i.e. extraction of a segment of video containing a golf swing or identification key swing positions, or both.
Examples of such existing methods are: Manually examining the video swing footage and identifying the segment showing the tennis swing and frames showing key motion positions. This is time intensive as it requires a user to look through all the video footage.
Detecting the noise of impact to identify the moment of impact has been disclosed in U.S. Pat. No. 6,537,076 and U.S. Pat. No. 6,567,536. The rest of the swing is assumed to be within a certain time either side of this moment. This method requires an audio detection device working with the video capture device. This method will not reliably work when there is noise in the environment. For example, when other players are playing tennis in adjacent tennis courts, the sound of impact can be falsely detected due to another player's stroke.
Using other types of sensor to detect parts of the swing, for example pressure mats, are disclosed in U.S. Pat. No. 2006/0281060. However, this method may apply only for sport like golf and will not apply for sport like tennis, where the player needs to move from one position to other.
U.S. Pat. No. 8,020,098 B2 discloses an impact detection unit comprising of microphone which is placed near the player. This invention may work only in sports where the player is not moving around. This may not work all the time for all types of sport involving a player hitting a ball, for example tennis.
A variety of devices are known in the art that can measure parameters associated with a swing motion of a sport. These devices generally require that a player take swings at a ball while being monitored by launch monitors, video devices and other measuring devices. However, such devices suffer from several deficiencies. Foremost among these is cost. Some types of launch monitors generally use radar technology in conjunction with the Doppler effect to measure the speed and position of the swing and ball. These launch monitors must be capable of emitting the precise type of radar necessary, as well as analyzing the shift in frequency due to the Doppler effect, in order to provide useful information to the player. The launch monitors therefore tend to be expensive, and can be especially cost prohibitive for amateur players. In addition, launch monitors can require professional calibration and set up to be able to obtain accurate information.
One such system is disclosed in U.S. Pat. No. 7,736,242 B2. Such systems are integrated and embedded within the sport equipment. Hence these systems cannot be used for monitoring swing motion of any other sports.
Hence there is a need in the art for a system and method that would allow amateur and professional players alike to be able to capture and analyze various aspects of their swings in an accurate and cost effective manner. The training devices should be such that it can be reliably used for any sport involving an impact to the sport equipment. Players should be able to use already-owned and/or everyday-used portable electronic devices as a training device. There is also a need that a user should be able to use the same training device to monitor the swing motion of various sports like tennis, squash, golf, cricket, baseball, basketball and the like.